Polyphase vacuum-tube oscillator



Jail. 13, 1931. A, GQJENSE 1,788,720

POLYPHASE VACUUM TUBE OSCILLATOR Filed July 6, '1927 2 Sheets-Sheet 1 Arramsr Jan. 13, W31. A. (a. JENSEN 1,733,720

POLYPHASE VACUUM TUBE OSCILLATOR Filed July 6, 1927 2 Sheets-Sheet 2 4 ,/n,, W Y m, n

. Patented Jan. .13, v 1e31 iixnn st em, nun nanidnnw JERSEY; nss'reuonro'nntt TELEPHONE LAB- onnron ns, rnconronarnn, on N YORKLN. Y., A'con1=onA*r1onor NEW. YORK, i

roL PHAsE vacuum-stuns. oscrn-Lii'ron l Application filed m 5, 1927. Serial no} 203313. 1

This invention relates to conversiont electric energy from one form to another, as

for example from direct current energy to alternatl'nir currentenergy, and also relates .to phase control.

In one specific aspect, the inventio-nrel'ates to. anoscillato'r comprising-a plurality of Vacuum tubes witha. plurality of tuned ire quency dete-rmini11gcircuits which have eleji'nen'ts conj-ugately relatedyfor causing, the) tubes to generatesustained polyphase oscillations.

In anotherspeciiic aspect the p W V 1's at1 .t-he; center of the two inductance icoils .a' polyph'ase vacuum tube oscillator which generates currents. 0f a greater number of phases ithan the number of space d scharge paths employed;

= Asis well known, aHartley-oscillator may, comprise a Vacuum tube with an inductance coil and a capacity-element each connecting, the grid and the plateotthe tube,;the,'-felec-" Y 1 tric'al mid-point oftheinductance coil being The oscillator lnay atford meansforsyary ing the phase relation of wavesgwhich the oscillator generateggandthushave wide apphcations in obtainlng voltages of variable phase relations.v One such application willu I 4 root, mean square i value of I the induced voltage fwill-' remain constant. p Another-secondary winding, having a fixed angular relation to "the two coils,- has. induced presently bementioned.specifically; pj connected to thelilam entof the tube. In the form of the present inventionshown in the. drawing, byIWay of-example, the capacity {element of such .an foscillator,insteadof be'-. 'ing in one unit isnlad'e upof ffour separate :units or condensers of equalcapaciti'ejs, two .1 beingconnectediinj series witheach other; across the plate :andg'rid .ofthe tube, andthe. other two being also connected in serieswith each othergacrosstheplate and-ithexgridv i.

This, of course,-does not;alter tlieifunction- .-,i-n'g otthe oscillaton A'second andlike os- CillatOr-erhploys the same four condensers as thecapacity element of its oscillation cir-' cuit,.haslitsgrid connected to'the-junction of the first two condensers, has its plate con-v nected to the junctionlof the other tWo condensers, has its filament'iconnectedto thatof thefirst oscillator, and-hasZthe inductance .equal to that ofthef first oscillator. The in- 4 ductance coils havethein axes at right angles coil of its oscillation circuit of inductance Spa jot-con out changing the :magnitude 1inthe-s rota'tablewinding. I

to each other and intersecting at the center M l i of each coil, and the circuit is symmetrical both mechanically andele'ctrica'l-ly. The 'enthe second coil, and the. potentials of the'four iefluzres from the coils being in time and quadrature, constitute a rotating fluxstantamplitude. A: secondary winding is rotatably; inounte,d sothat itscenter angularv position of the winding-1 and the in it-f1ioin',.one or both-1 of the coils a voltage offixed magnitude and phase. Thus,1by ro- 1 i V tating ,theinovable secondary winding the "pliasejirelatiombetween the voltagespin-theg l7 twq d y windings can-be variedgrritl of thegblt g i Fig. -1 isacircint diagrarnifof:anenibodi g 5,

'Inent: of the invention Fig. '2 is. a-. perspec- JI tivet iew showing. the relative space arrangenieiit 1 of the" .oscillatorQinductance coils and ends oft-he coils with respect-to the'lcomnion i inductance midepointare 90;apart inyphase.

thefixed:phase-winding land the'-*rotatable variable phase winding which are coupled to the oscillator inductance coils, ai portion. of.

one oscillator coil being shown: broken away :.-that the rotatable :windingq may be seen more clearly; Fig; 3'isa"schernatic1diagramof thaxoscillator; circuit; Fig tis a Vector '95 mplitudes ofthe [Voltages across the inductance 1 diagram showing the relative phases and ana coils and T the condensers "of i the oscillation modification of "the condenser system" of the circuits of thef-.-osc illator; Fig.; 5 shows I metrically arranged on a cubical frame 7 as shown in Fig. 2. In the schematic diagram of Fig. 3, one end of each of the four coils is grounded, and between each two of their other ends is connected one of the condensers, respectively. The filaments of tubes O5 and 0&6 are grounded through conductors 8 and'9 respectively, as shown in Fig. 1. Coil L is connected, in series with a grid biasing battery 10, between the grid 11 and the filament of the tube O5, through conductors 12 and'13. Coil L is connected, in series with plate current supply battery 14, jbetween the grounded filament and the plate 15 of tube O5, through conductors 16 and 17. ,Coil L is connected, in series with a grid biasing battery-18, between the grid'20. and the filament of'tube-O6,ithrough conductors 21 and 22. Coil L; is connected, in

series with the plate current s'upplybattery 14, between the grounded filament 'and the plate 23 of tube O.6, through conductors 16 and 24. Condensers 25 and 26 of large capacity prevent the voltage of battery 14 35' from reaching grids 11 and 20, respectively. hen the four condensers C C ),'Cg and C are alike and the circuit is symmetrical, me-

chanically as well as electrically,the'entire system will oscillate at one frequency only,

and the voltages across the coils L andL will be equal in amplitude to, but 902mm ofiphase with, the voltages across the coils" I If the entire oscillatory system is perfectly 'fsymmetrical it will representa bajlanced bridge circuit, and: a voltage impressed across the inductance coils L and L in Fig. 3, will induce no voltage across thecoilsiL 'and L The system therefore will oscillate atfone. frequency-only, as long as the four'coils L),

L L5 and L and the four condensers C C C and C are exactly alike, and may oscillate at two different frequencies if one oftli'ecoils or condensers is changedfslightly.

It has been found in rpracticeyhowever,

that enough coupling will always exist between the two halves; of the system to make the entire system oscillate at one frequencyonly, as long as the four coils and condensers are approximately alike. A proper variation: of the condensers'may therefore be used in adjusting the phase V relations correctly, as

*in accordance with 'amethodto' be described later, without:v disturbing; the synchronism.

The relative-phases and amplitudes ofjthe located; 7 V Theoretically, the most convenient way-of voltages Z Z Z Z 0 0 0 and across coils L L L and L and condensers C C C and C respectively are indicated in the vector diagram of Fig. 4. It will be seen that although only two vacuum tubes are employed, four voltages 90 apart are available,

a as for example voltages c c c and 0 across condensers C C C and C respectively.

As indicated in Fig.2, a coil 30 ismounted for rotation by a dial 31 so that the center of thcc'oil is at the center of the cubical frame 7 and the axis-of the coil can have any di rection or angular position in the plane c0ntaming the axes ofthe coils L L L and L As the coil 30 is rotated through 360 the phase of thevoltage induced in it from the coils L1, L L and L will vary through a phase angle of 360 in linear proportion to the variation in the angular position of the coil 30, and the root means square'value of the induced voltage will remain constant.

A coil 85 having a fixed angular relation to the coils L L L andL has induced in it from those coils a voltage of fixed phase. As shown, the coil 35 is coaxial .with coils L and L ,.and' therefore the voltage induced in it is due substantially entirely to the currents inwindings L and L the coil 35 being noninductiv-ely related to coils L and. L to the axis (if-which itsaxis is aright angles. However, the coil 35 may be magnetically coupled to the coils L L L and L; in any suitable or convenient way. If its position 'with respect to coils LhiL L and L is fixeththemagnitude of the voltage induced in it. is constant; but if desired'the magnitude may be variedby moving the coil 35 toward or away from the center of the cubical frame 7 whilelreeping the direction of the coil axis fixed; It will be seen that, by keeping the 1 coil 35fixed'in positionandrotating'the coil 30 the phase relation between the voltages in these coils can be varied as desired without changing the magnitude .of either voltage.

Although the. coils L L L and L have been :shown arranged on a cubical frame with therotatable coil 30 mounted in the center of the cube and with the'fixed coil 35 mounted coaxial with coils L and L it'is possible to use any ofvarious symmetrical arrangementsof'the" coils giving afairly uniform field at the point where the movable coil is arranging the circuit would be to have the fourvariable condensers mountedon a com mon shaft so that the adjustment of the oscillator to any given frequency would require onlycne tuning as forfordinaryoscillators.

However, with such an arrangement it would be found rather difficult'to arrange the condensers in such away-that mutual capacities and-ground capacities were balanced out;

and the'result wouldbe that the volta e across coils L andL. v would not be exact y 90 out of phase with that across coils L5. and

' L i over the entire frequency; range'of the i them all from the same shaft.

7 it is jconvenient to 'mechanical oscillator, andtherefore-the Voltage induced the coil'30' would vary in'amplitude aswen as in phase,upon rotation 'of thejcoil.

In order to avoid ,tlus amplitude variation,

ly couple the condensers in pairs,'-instead of controlling condensers C and C51 may be mounted on the same shaft and varied simultaneously, as 1n'd1- cated'by the connection between these conto Widely different oscillator may oscillate at two diiferent fre-V i ently,

densers" in Fig'i 1'; and similarly the condens *ersgC and C r'nayfbe mounted upon the "same shaft as indi'catedby connection 41.

If these two sets *of condensers are adjusted capacity alues, then the quencies simultaneously,whil oscillations of asingle frequency gonly will'be generated nection With double adjustment of the jphase relation of the yol-f tage across coils :Lgand L 7 variation Without appreciable change in l to theyolta'ge across coils L 'and-"Lgc'an be made by connecting the rotatable coil 30in the input-circuits of the intermediate frequency detector, connectinga telephone headset in the-plate circuit of thisdetector, 7 arying the condens headset is obta ned asan indication that only a single frequency ers until zero-beat in the is being generated, and thereupon adjusting the twosets of condensers slightly until a deflection on a metersinserted inthe inter-;

mediate frequency detector plate circuit stays constant for all "positions; pf the", ariable phase coil 39.

phase relations is obtained by turning the two; condenser shafts the same amount inthe' same direction; hilea relative phase change" between the. fcu-rrentfin icoilsQLj, and L and the-currentin coilsiL fand L ,"\i ithout any appreciable frequency change, is obtained by turning the two con'densershaftsthe same I amount in opposite directions, to increase the g I capacit es of two of the condensers a given 2 amount and decrease the capacities of the ,other condensers the same amount.

. receiver as described above for adjustingthe phase relations in the oscillator, the adjustment can i be accomplished by connecting'coil g L, across one pairof plates inacathode' rayvariable condensers so-tha't theyareyaried "Thus, I the Instead of employing V a double detection 1;f A system r-forithe;

then adjusting the Variable 1 in pairs,,they can, as indicated injFigs. 5

and 54A, all four be niecha nically'connected together by a connection,indicated at45, so

ofthe other two are decreased. A variation of the ye1u1iercondensers Willresult "in a phase cha11ge ma1nly,, In Fig- 5'A the means for varying the two pairs of ernier 'condensersis indicated-asaj bar 55 connect ing thetwolpa rs and rotatable by a "(l-Fill :of the large condensers Will then result" in a frequency change malnly, Wh le a var ation knob 56. "(llockwiserotation of the'knob in t creases theicapacities oficondensersfil' and 52s an'dfdecreases, the capacities of condensers 53 and 54; Counterclockwise rotation 'o f con 'nection 55 has theiopposite efiect.

tainin'g *from coils 30 $35 two'- different neterodyne or beat ng oscillatorv jvoltages-"cf One application Of'the nvention is in ob Variable relative magnitudes" h and yari'able' Friis, Proceedings of the Institute of Radio Engineers, volume 113', pages i 685130 70751136 cember; 19251 VVith such beating oscillator {phase difl erencesfor example; for usegin afl directional double detection radio receiving system-'of'the general: type'describedby H. :T. V p

voltages available, directional: selectivitycan be obtained, as explained inthejFriis'article, I

bybalanc'ing or combiningiproperly twoin- 'termediate frequency WaVefs fobtained-"by i-ntermodulatin'g the 'fitwo'fos'cillator voltages respectively with two signal L- 'yoltages received from two; similar loop antennae prop- V V f 1 e'rlyr"positioned"Withrespectto each other; ln'the'operatlon of the oscillator, frequency As explained in the article, by controlling the relative. magnitudes and tllejpllasrela tioniof the oscillator 'currentsin such a-system, the relative "magnitudes and the orreinforce each other as desired, andithererby causeithesystem tojhayeia:desired d1rec-. I

tional characteristic as regards the. relation 5 between the magnitude of the" resultant: in termediate frequency voltage; and the :(lll'reC- $1011 from Wl11Cl1 the rece ved-radio waves are incident; upon theiantennze' is claimed is; t

generation of plural phase current comprising generators, each comprising an electric dischargedevice r and an assoclat at least a portion; :of each said frequency determining 1 circuits being 4 in common "with the others, saidgeneratOrsbeing less num- I her than the number of phases of theresultant "p'olyphase wave directly generatedftheref by, and meansfor associating said generators V to :maintainthem in'synchronism and their potentials in thedesired phaserelation.

2. A polyphase spacedischarge oscillator system comprising space discharge paths and an equal number of frequency determining oscillation paths associated therewith, at least 7 a portion of each of said paths being in common with the others, said paths being so interrelated that the'numbcr of phases of I the resultant polyphase voltage directly gendischarge paths in the system. 7 r

3; Thecombination with electric space diserated is greater than the number of space charge tubes of frequency determining oscillation circuits partially common to allof said tubes, for causing said tubes to generatesusand another of said a synchronizing circuitfincluding a closed current path, anode, cathode and discharge control elements included in each of said converters,a portion of said closed current path being connected betweenan anode ele ment and another ofsaid elements of one of said valves and between anv anode element elements of another of said valves.

10. Ina system for converting direct current power into polyphase alternating currentpower, a valve converter comprising electrostatically and .r'egeneratively controlled tained voltage oscillations, and soassociated with-each other: and with the tubes as to maintain a phase diflerence substantially less than 180 degrees between two of said voltages.

4. In combination, electric space discharged tubes and tuning circuits for caus ing said tubes to generate sustained oscillations, said circuits having reactance" elements common to all saidtubes and .other reactQ ance elements individual tosaid tubes.

points in saidbridge; 7

.5. In combination, electricspace {discharge tubes and oscillation circuits-for causing said tubesto generate sustained oscillations, said circuits comprisingin common a bridge network, the remaining elements of the respective, circuits being-connected to conjugate 6.-;An electric space discharge device, an

oscillation circuit'for causing said device to .valves and means connecting said valves in such symmetrical circuitarrangement as to maintain them insynchroni m and cause them to directly generate polyphase current of a-- number of phases greater than the number of said valves. I V

11. The combination with an alternating current electric space discharge generator comprising four or more'current' paths con nected in a closed circuit andmeans for creat- .ing voltages in each of-saidpaths, of station ary :means producing an additional voltage connected across said circuit at such points thatj two of-the first voltagesjare in series with the additional means. 1

.12. In combination, anelectric space discharge osc llator tube, an oscillation clrcuit therefor, a second electric space discharge oscillator tube, an oscillation circuit theretwo circu'it s,.a current path in said first circult connected between two pointsof said generate "sustained oscillations, and means.

included in said circuit for creating a magnetic field rotating inspace.

7. A system for theageneration 'ofpoly phase current comprising a plurality of space discharge generators, frequency determining circuits therefor, and a closed loop circuitof said generators. V

8. A. system for converting direct current power into polyphase alternating current power, comprising a plurality of electrostatically controlled valveshaving anode, cathode and discharge control elements, means. for

in the frequency determining circuit of each .regeneratively controlling said -valves and maintaining said valves in synchronism and in polyphase-relation, a current path between an anode and a control element of one'of said valves-,1ncluded in said means, and acurrent path between an anode and aacontrol element ofanother of said valves, included in said means and partially" included in said first path. 7 I r I 9. A system for converting direct current .*power into polyphase-alternating current power, comprising electrostatically and regeneratively controlled --valve' converters. as-

- sociated with circuit paths which; constitute included incommon and in a similar relationv for, a, closed current path common to said closed path, and a current path in said second circuit connected between two other points of said closed path. I

, 13. In'combination, electric space discharge oscillator tubes each having anode, cathode and discharge controlgelements, a network associated with said elements for causing said tubes to generate polyphase cur rent, an inductance coil included in said net work connected between two of said elements actance elements having reactances of like sign and equal magnitude in series in said circuit, means connecting two of said elements of one of said tubesbetween the junction point of two of said'reactance elements and the junctionpoint of the othertwo of said reactance elements, means connecting .two of said elements of the other of said tubes between the other two junction points of saidrea'ctances, two'equal reactance elements of sign oppositeth-at 'ofsaidfirstre-c.

actances, mean s1 connectingone of saidtwo reactance elements across said two elements ofsaid one tube, and meansconnecting the other of said two reactance elements across said two elements of. said other tube.

15. Incombinationftwo inductance ,coils having their axes in a given plane, electric vspace discharge oscillator tubes, means so associating saidtubes and said coils as to cause said coils toproduce harmonically va rying magnetic fields in time and space quad- ,rature relation and of substantially. equal maximum magnitudes at a given point, a third inductance coil,1and means mounting c said third coil for rotation at said point with its axis in said given plane. v j V 16. An oscillator comprising two electric space discharge tubes, each havinganode, cathode, and discharge control elements, four condensers in series forming a closed circuit, means connectlng two of said elements of one of said tubes across two of the junction points of said condensers, means connecting j two'of said elements of said other tube across the other junctionpoints of saidcondensers, two equal inductance elements, one connected across said two elements of said onetube and one connected across said two elements of said othertube, means'jlfor varying the ca-v pacities of two of said condensers the same amount 11113118 samedirectiomand means for l varying the capacities of the remainingtwo condensers relative tothe capacities of said first two condensers while maintainingthe capacities of said remaining two condensers equal to each other.

I 17. An oscillator comprisingtwo electric space discharge tubes each having anode, cathode and discharge control elements, four 7 condensers in seriesforming a closed circuit, means connecting two of said elements of J one of said tubes across two ofthejunction points of said condensers, means connecting two of said elements of said'other tube across the other two junction points of said condens ers, two equal inductance'elements, one c0n-' nectedacross said two elements ofsaid one tube and one connected across said two elements of said other tube, means forsimul- ,taneouslyvarying thecapacities of each of said condensers jby substantially the same -1 amount in the same direction, a' c-ondenserof relatively small capacity connected across each of said first mentioned condensers and means for simultaneously incre'asingthe capacities of two'of said small condensers and decreasing the. capacities of the remaining two ofsaid said small condensers. I i

In witness whereof,I hereunto subscribe T my name this 17th day of J une,'A. D. 1927 ,4 YAXVEL e. JENSEN. 

